Activation properties of heterologously expressed mammalian TRPV2 - Evidence for species dependence
Activation properties of heterologously expressed mammalian TRPV2 - Evidence for species dependence
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DOI：
10.1074/jbc.m608287200
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发表时间：
2007-05-25
影响因子：
4.8
通讯作者：
Qin, Ning
中科院分区：
文献类型：
--
作者：
Neeper, Michael P.;Liu, Yi;Qin, Ning
TRPV2被认为是一个潜在的疼痛靶点，部分原因是它与伤害感受器TRPV1的关系，以及它在有害高温（bb0 - 52℃）下的激活。然而，TRPV2对热的反应以及对非选择性激动剂2-氨基乙氧基二苯硼酸盐（2-APB）的反应尚未在其他实验室普遍重现，这导致了对该通道激活特性的争论。在这里，我们报告了大鼠、小鼠和人TRPV2在HEK293细胞中的表达，以及它们对热和2-APB反应的差异特性。小鼠或大鼠TRPV2在HEK293细胞中的表达，在温度（bb0 ~ 53℃）或2-APB诱导下均可产生强大的通道激活。相比之下，人类TRPV2的表达在这两种刺激下都没有导致可检测到的激活。人类TRPV2蛋白的表达水平与大鼠TRPV2相当，具有相似的表面定位，并对新发现的TRPV2激动剂Delta(9)-四氢大麻酚有反应，表明人类TRPV2在细胞表面有功能表达。对大鼠和人TRPV2缺失突变体和嵌合体的研究表明，大鼠TRPV2的氨基和羧基细胞质末端对热反应和2-APB都很重要，但可以通过反式提供形成活性通道。本研究不仅证实并扩展了先前的报道，证明大鼠和小鼠TRPV2对2-APB和有害热有反应，而且表明需要进一步研究来阐明TRPV2的激活和调节机制。
TRPV2 has been proposed as a potential pain target, in part due to its relatedness to the nociceptor TRPV1 and to its reported activation by noxious high temperatures (> 52 degrees C). However, TRPV2 responses to heat as well as to the nonselective agonist 2-aminoethoxydiphenyl borate (2-APB) have not been universally reproduced in other laboratories, leading to debate about the activation properties of this channel. Here, we report the expression of rat, mouse, and human TRPV2 in HEK293 cells and the differential properties of their responses to heat and 2-APB. Expression of mouse or rat TRPV2 in HEK293 cells resulted in robust channel activation when induced by either temperature (> 53 degrees C) or 2-APB. By contrast, expression of human TRPV2 did not lead to detectable activation by either of these stimuli. Human TRPV2 protein was expressed at levels comparable with those of rat TRPV2, exhibited similar surface localization and responded to a novelly identified TRPV2 agonist, Delta(9)-tetrahydrocannabinol, indicating that human TRPV2 is functionally expressed on the cell surface. Studies using deletion mutants and chimeras between rat and human TRPV2 indicated that both amino- and carboxyl-cytoplasmic termini of rat TRPV2 are important for responses to heat and 2-APB but can be supplied in trans to form an active channel. The present study not only confirms and extends previous reports demonstrating that rat and mouse TRPV2 respond to 2-APB and noxious heat but also indicates that further investigation will be required to elucidate TRPV2 activation and regulatory mechanisms.